81130658585681 has 2 divisors, whose sum is σ = 81130658585682. Its totient is φ = 81130658585680.

The previous prime is 81130658585677. The next prime is 81130658585761. The reversal of 81130658585681 is 18658585603118.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 79318902205456 + 1811756380225 = 8906116^2 + 1346015^2 .

It is a cyclic number.

It is not a de Polignac number, because 81130658585681 - 2² = 81130658585677 is a prime.

It is a super-2 number, since 2×81130658585681² (a number of 29 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81130658585671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40565329292840 + 40565329292841.

It is an arithmetic number, because the mean of its divisors is an integer number (40565329292841).

Almost surely, 2^{81130658585681} is an apocalyptic number.

It is an amenable number.

81130658585681 is a deficient number, since it is larger than the sum of its proper divisors (1).

81130658585681 is an equidigital number, since it uses as much as digits as its factorization.

81130658585681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 55296000, while the sum is 65.

The spelling of 81130658585681 in words is "eighty-one trillion, one hundred thirty billion, six hundred fifty-eight million, five hundred eighty-five thousand, six hundred eighty-one".